Anticorrosive metal article and method of making same



Patented Dec. 30, 1952 ANTICORROSIVE METAL ARTICLE AND METHOD OF MAKING SAME Johannes A. van Melsen, Amsterdam, Nether-, lands, assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application Ma 'si, 1947, Serial No. 751,635. In the Netherlands March 14, 1941 Section 1, Public Law 690, August 8, 1946 Patent expires March 14, 1961 13 Claims.

1 This invention relates to corrosion inhibitors for protecting various metal surfaces, such as ferrous and non-ferrous metals, metal alloys, and the like, from corrosive and oxidative action of air, moisture, salt brines, acids, gases such as S02 and S03, and the like. Corrosion inhibitors of this invention in addition to protecting the metal surfaces from attack by corrosive materials, inhibit formation of acidic and deterioration products from forming in initially non-corrosive liquids which-act as carriers for corrosion inhibitors, as coolants, penetrants, hydraulic fluids, anti-freeze compositions and the like, thereby additionally protecting the metal surface from corrosion by these metal contacting liquids.

Metallic surfaces exposed to corrosive gases or when in contact with corrosive liquids or liquids which tend to decompose and form corrosive bodies which readily attach and corrode metal surfaces with which they are in contact, require protection against such damage. Thus moisture entering the cooling, fuel and lubricating systems of internal combustion engines, steam turbines, and the like, readily attack and corrode various metal parts of such systems, this not only has a deleterious efiect upon the metal surface, but

also frequently loosens finely divided metal oxides which may act as oxidation catalysts, increasing the rate of deterioration of the contacting liquids, or which oxides may enter movable parts of the engine and act as abrasives, causing fouling and plugging of the circulating systems.

Moisture is not the only agent which causes corrosive damage to metal surfaces. composition materials formed in engine liquids during use attack metal surfaces and in addition to causing corrosion, result in gumming and sticking of movable metal parts as well as formation of lacquer, varnish and carbonaceous materials. Thus anti-freeze compositions for automobile radiators, hydraulic brake and shockabsorbing fluid deteriorate and corrode metal surfaces. In addition metal chemical equipment, steel drums, structures, instruments in contact with moisture, corrosive gases and liquid compositions, are readily attacked and corrode.

Various substances have been tried for preventing corrosion of metal surface. In the majority of cases such compositions comprise an oleaginous base, such as mineral lubricating oils, fatty oils, greases, and the like, containing minor amounts of corrosion inhibitors, such as natural or synthetic. resins or waxes, cellulose esters or ethers, wool fat, paraffin Wax, asphalt bitumen, metal soaps, such as metal stearate; metal naph- Acidic dethenate; metal resinates, preferably the barium magnesium and aluminum resinates; pigments such as chromate yellow, ochre, zinc oxide, titanium oxide, etc.; and substances with bacteriocidic or algacidic properties, such as copper arsenate, and the like. In the majority of cases compositions of this type have proved to be of little value due to their relatively short life as corrosion inhibitors and their inability to prevent deterioration of organic liquid with which they are admixed.

It is an object of this invention to treat metals in a simple and convenient manner so that they may resistcorrosion. Another object is to protect ferrous and non-ferrous metals and their alloys from rusting and corroding when exposed to corrosive conditions. Still another object is to protect from corrosion chemical and mechanical metal equipment in contact with various organic compositions which are susceptible to deterioration and acidic formations by stabilizing such compositions. Furthermore, it is an object to chemically rust-proof metal surfaces and stabilize contacting liquids by dispersing therein a rust-proofing agent of this invention.

It has now been discovered that metals subjected to corrosive influences can be protected simply and effectively by dispersion in a nonlubricating liquid, preferably a non-lubricating petroleum hydrocarbon liquid, boiling below about 600 F., a polyvalent metal salt or soap of an aromatic monocarboxylic acid, having, if desired, attached to the aromatic nucleus various substituent groups.

Corrosion inhibitors and metal rust-proofing polyvalent salts of aromatic monocarboxylic acid applicable for this invention can best be illustrated by the general structural formulas:

wherein Q represents a mono or polyaromatic radical; R. is an alkyl or aryl group; m is either one or zero, in which latter case the carboxylic acid radical would be attached directly to the aromatic ring Q; Y represents a radical selected from the group consisting of oxygen or S03; R represents an alkyl, alkaryl, aryl, aralkyl, amino, nitro, alkoxy, or aroxy group; X'can be hydrogen or acid equivalent metal; a and bare integers, one sum of which should be equal to the number of available nucleur carbon atoms on the ring Q and M isa polyvalent metal selected from groups II, III and VIII of the periodic table.

Polyvalent salts of aromatic monocarboxylic 3 acids can also be represented by the inner salt formula:

R'QRCOO g wherein the symbols correspond to those used in Formula 1.

The polyvalent metal salts of aromatic mono carboxylic acids can be prepared by any convenient method. Among the polyvalent metals which can be used are: beryllium, magnesium, calcium, zinc, strontium, cadmium, barium, aluminum, indium, iron, cobalt and nickel. Preferred polyvalent metals are calcium, colbalt, zinc and nickel. acids may be mono or polynuclear, having attached to said nucleus, if desired, substituent groups such as alkyl, aryl, alkoxy, aroxy, alkaryl, hydroxy, amino, nitro, or sulfo radicals. Ex: amples of aromatic monocarboxylic acids and substituted monocarboxylic acids are: benzoic acid, nitrobenzoic acid, aminobenzoic acid, tertiaryl butyl benzoic acid, 5 hydroXy-1,3 dimethyl benzoic acid, 6 hydroxy-l,2 dimethyl benzoic acid, 6 hydroxy-l,2 dimethyl benzoic acid, 3,6 dimethyl-2-hydroxy benzene-l-carboxylic acid, anthrandic acid, thymotic acid, cresotic acid, octyl cresotic acid, oxyphenyl cresotic acid, 5-ethyl-2,-4 cresotic acid, sulfobenzoic acid, alkyl sulfobenzoic acid, salicylic acid, isomericmethyl isopropyl salicylic acid, diisopropyl salicylic acid, dimethyl salicylic acid, carvacrotic acid, oxytoluic acid, cinnamic acid, phenylstearic acid, phenyl propiolic acid, diphenyl glycollic acid, atropic acid, gallic acid, vanillic acid, proto cutechuic and alkyl protocathechuic acid, resorcylic and alkyl resorcylic acids, anthroic and alkyl anthroci acids and the like.

Of the acids mentioned, not only the neutral salts come into consideration, but also the salts which contain more metal bound than corresponds with the composition of the neutral salt, such as the basic salts, their anhydrous compounds and the inner salts; examples are the basic zinc salt of tertiary butyl benzoic acid, the

inner calcium and zinc salts of diisopropyl salicylic acid. The basic cobalt salt ofthymotic acid and the like.

A typical salt of this invention can be made as follows:

(A) Preparation of dzfisopropyl; salicylic acid- Approximately 4.8 mols of 92% H2804 is stirred into a reaction vessel containing approximately 2.4 mols of di-isopropyl ether and mixed for about 10'minutes at which time the mixture attains a temperature of about 70 C. The temperature of the mixture is increased to around about 90 C. and about 2 mols of salicylic acid is slowly added to the mixture, carebeing taken that the temperature does not rise above about 100 C. This composition is maintained at between about 95-l00 C. for about hours after which it is cooled and admixed with gasoline and water under agitation. The sulfuric acid layer is removed and the gasoline layer washed with an approximate equivalent volume of Water.

The diisopropyl salicylic acid is removed from the gasoline by mixing with a 10% caustic solution. The sodium salt solution thus obtained is washed with gasoline and subsequently acidified with 4N sulfuric acid. The di-isopropyl salicylic acid is separated off, filtered, washed with water and dried.

The aromatic .monocarboxylic 4 (B) Preparation of zinc salt of diisopropyl salicylic acid Di-isopropyl salicylic acid prepared in the manner indicated above is heated to around about -l18 C. and a quantity of zinc oxide, preferably around about 20% higher than is necessary to neutralize the acid is added and the mixture carefully heated to about -l25 C. for about half an hour. The mixture is then dissolved in ether or some other solvent, filtered and the solvent evaporated.

The zinc salt can be made from the dilute caustic soda solution referred to in part A by converting the sodium salt into the zinc salt by addition of 'zinc sulfate. The zinc salt of diisopropyl salicylate can then be extracted from the aqueous solution with the aid of gasoline and obtained in the dry state by evaporation of the solvent.

(C)Preparation of inner ring salts of zinc dz'isopropyl salicylate A salt as prepared in part B is dispersed in a suitable diluent having a boiling point above 200 C. and the mixture heated above about 160 C. and preferably between about l90200 C. until carbon dioxide evolution has ceased. The transformation of the zinc salt from an open The inner salt is removed from the diluent by any convenient manner such as distillation, etc. Inner'salts are preferable especially when dis! persed in non-lubricating petroleum hydrocar-s bon boiling below 600 F. since they dissolve more readily therein.

The vehicles to which the polyvalent .metal aromatic mono-carboxylic acids ofthis invention.

may be added for the purpose of producingcon. rosion-protecting compositions maybe polar and non-polar vehicles which are spreadable. over metal surfaces. by immersing, flooding, spraying, trowelling, flushing, contacting, etc.

After being applied all or part of the .Vehicle brushing,

may evaporate, or it may be. more. or less .per- It is preferable to use as a carriersub-- manent. stances which do not materially volatilize under normal atmospheric conditions. As tov chemical requirements, the vehicle. must, be stable under ordinary conditions of storagev and use and be inert to the active inhibitors.

Among the vehicles which can be used are nor-- mally liquid petroleum hydrocarbons of nonlubricating range boiling below about 600 F. such as normal hextane, 2,2,4 .trimethyl pentane, 2,2,5,3, tetra methylbutane, 2,5 diniethylhexane,

normal octane, nonane, decane, dodecane, ethyl;

cyclohexane, isopropylcyclohexane, toluene, pxylene, o-xylene, M-xylene, cumene, petroleum naphtha, mineral spirits which are distillates obtained from petroleum having a boiling range of between about -2l6 Spreading may be accomplished.

C. and a flash point.

of 100 C., kerosene, Stoddart solvent, mineral seal oil, gas oil, gasoline, other light petroleum distillates; turpentine, halogenated hydrocarbons such as ethylene dichloride, trichloroethylene, propyl chloride, butyl chloride, chlorinated kerosene, alcohols such as methyl, ethyl, propyl, isopropyl, butyl, amyl, hexyl, cyclohexyl, heptyl, methyl cyclohexyl, octyl, decyl, lauryl, myristyl, cetyl, stearyl, benzyl, etc., alcohols, polyhydric alcohols, such as glycols, glycerols, etc, esters of monohydric alcohols and aliphatic mono and dicarboxylic acids such as oleic, ricinoleic, adipic sebacic, succinic, phthalic acids.

The amounts of corrosion inhibiting polyvalent metal-aromatic monocarboxylic acids which must be incorporated into the above vehicles to stabilize the vehicle and produce a corrosion-protective composition depends upon the vehicle, the condition under which the composition is used and the metal being protected. Generally between about 0.1 to 2% by weight and preferably about 1% is all that is required. The addition of larger quantities being superfluous from the point of view of activity.

The following examples will serve to illustrate the manner of practicing the present invention, although they are not to be considered as limiting the scope of the appended claims.

EXAMPLE I Test pieces of iron plaque were coated with:

A. 3% seawater emulsified in a Venezuelan refined petroleum distillate. .B. Composition A containing 0.1% zinc salt of di-isopropyl salicylate. The iron plaques were kept at a temperature of about 90 C. and the formation of rust observed.

Bust-inhibiting composition Appearance of iron plaque Intensive rust formation observed after 2 hours. No rusting observed.

A. 3% seawater emulsified in a refined petroleum distillate.

B. 3% seawater emulsified in a refined petroleum distillate containing 0.1% wt. of Zn salt of diisopropyl salicylate.

EXAMPLE II EXAMPLE III A series of tests were conducted for a period of two weeks in which test pieces of clean steel were exposed to the atmosphere, some were exposed to the atmosphere after being brushed or sprayed with liquids enumerated below while still others were coated with the same liquid vehicles but contained from 0.1 to 2% by wt. of polyvalentmetal-monocarboxylic acid corrosion inhibitors of this invention.

Appearance of Metal Diluent Additive steel test piece 1 after 2 weeks 1. Steel..- None None Rusted badly. 2. Steel... Kerosene o Do. 3. Steel... .do 0.1% Ca salt of diiso- No rust after 2 propyl salicylate weeks. 4. Steel... .--..do 2.0% Zn salt of diiso- Do.

propyl salicylate. 5. Steel-.- .do 2.0% cobalt salt of thy- Do.

motic acid. 6. Steel-.- .-.-.(lo 2.0% Zn salt of tert. Do.

butyl benzoic acid. 7. Steel..- Trilchloroeth- Rusted badly.

y ene. 8. Steel.-- .-...do 2.0% Zn Salt of dllso- No rust after 2 propyl salicylate. weeks. 9. Steel... ...-.do 2.0% Go salt of thy- Do.

motic acid. 10. Steel.. ..-..do 2.0% Zn salt of tert. Do.

butyl benzoic acid.

If desired other corrosion inhibitors can be added to compositions of this invention. Among them can be included sulfonated castor oil, blown vegetable and fish oils, waxes, organic derivatives of acids of phosphorus such as aliphatic and aromatic esters of acid of phosphorus, organic derivatives or inorganic acids, e. g. sulfuric, silicic and nitric acid; mercapto and cyano monocarboxylic acids; fatty acid amides and the like.

When difficulty is encountered in dispersing salts of this invention in a particular carrier, a solubilizer can be used such as sulfonates, alcohols, esters, acids and the like.

Many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim as my invention:

1. In a method of inhibiting corrosion and rusting of a metal surface which normally is subjected to oxidation and corrosion conditions by applying to said metal surface a, corrosion protective composition comprising a relatively volatile non-polar liquid carrier and an efiective corrosion-inhibiting agent, the improvement which comprises utilizing as the corrosion-preventive composition a composition consisting essentially of a normally liquid petroleum hydrocarbon of non-lubricating range boiling below about 600 F. and from about 0.1 to 2% by weight of zinc diisopropyl salicylate.

2. In a method of inhibiting corrosion and rusting of a metal surface which normally is subjected to oxidation and corrosion conditions by applying to said metal surface a corrosion protective composition comprising a relatively volatile non-polar liquid carrier and an efiective corrosion-inhibiting agent, the improvement which comprises utilizing as the corrosion-preventive composition a composition consisting essentially of a normally liquid petroleum hydrocarbon of non-lubricating range boiling below about 600 F. and from about 0.1 to 2% by weight of calcium diisopropyl salicylate.

3. In a method of inhibiting corrosion and rusting of a metal surface which normally is subjected to oxidation and corrosion conditions by applying to said metal surface a corrosion protective composition comprising a relatively volatile non-polar liquid carrier and an effective corrosion-inhibiting agent, the improvement which comprises utilizing as the corrosion-preventive composition a composition consisting essentially of a normally liquid petroleum hydrocarbon of non-lubricating range boiling below about 600 -1*.ar1'cffrom about'0.1 to"2% by weight of cobalt diisopropyl salicylate.

4. -In'a1method of inhibiting corrosion and rusting-org, metal surface which normally is subjected to oxidation and corrosion conditions by applying to said metal :surface a corrosion protective'composition :comprising a relatively volatile non-polar liquickcarrier and an effective corrosion-inhibiting :agent, the improvement which comprises utilizing as the corrosion-preventive composition a composition consisting essentially of a normally liquid petroleum 'hydrocarbon'of non-lubricatingrange boiling below about 600 F. and from about 011' to 2% by weight of calcium salt of thymotic acid.

5. In a method :of inhibiting corrosion and rusting of a metal surface which normally is subjected to oxidation and corrosion conditions by applying: to *said metal-surface: a corrosion protective composition vcomprising a relatively. volatile non-polar 'liqu-idcarrieriand an effective corrosion-inhibiting agent, the improvement which comprises utilizing as the corrosion-preventive composition-a composition consisting essentially of a 'normally-liqui d petroleum hydrocarbon of non lubricating mange :boiling below about 600" F. and from about-"0.1 to 2% by-weight oicobalt salt OfLthymoti-c acid.

6. In'a method ofiinhibiting corrosion and rusting of metal surfaces by applying to said metal metal-hydroxy aromatic monoecarboxylic add salt.

8. An article of --manufac.ture, =a -corrodible metalprotected with acoating-of corrosion preventive composition consisting essentially of :a normally liquid polar and non-polarvehicle and from about 011% to 2% by weight-cf zinc diisopropyl salicylate.

.9.'An article of manufacture,- a corrodible metal protected with a coating of corrosion-preventive composition consisting essentially of a normally liquid. polar and non-polar vehicle and from .::about 0.1 to 2% by weight of a calcium 'diisoprop'yl'salicylatc.

10. An article of manufacture, a .corrodible metal protected with acoating of; corrosion-preventive composition consisting essentially .--of v.a normally 1 liquid polar and: nona-polar :vehicle and from :about :.O;1;% to :2:% by :weight of "ac'cobalt diisopropyl salicylate.

,ll.;An article .of manufacture, a corrodible metalrzprotected with a coating "of, corrosion-preventive ;.composition :consisting essentially. of a normally 1 liquid polar and. nonepolar .vehicle and from\.about 0:1% to::2% .by weight of a calcium salt of thymotic acid.

.l2.,An articleof manufacture, .a .corrodible metaltprotectedxwithta, coating of;;corrosionpr.e ventive acomposition consisting essentially of ;a normally liquid-.pclarsand 1 110111130131 :vehicle and from about 0.1% to 2% by weight of a cobalt salt of thymotic acid.

13. In a method of inhibiting corrosionxa-nd rusting of metal surfaces by applying to .said metal surfaces normally liquid polar and'nonpolar vehicle and from :about O;1% -to 2% by weight of a polyvalent metal hydroxy aromatic monocarboxylic acid salt.

J QHANNES A.- MAN MELSEN.

REFERENCES CITED The following references are of record in the file of this patent:

.UNITED STATES PATENTS Number Name Date 2,311,505 Archibald ',F eb.,16, 1943 2,334,158 Von Fuchs 1 Nov. 9, 1943 

6. IN A METHOD OF INHIBITING CORROSION AND RUSTING OF METAL SURFACES BY APPLYING TO SAID METAL SURFACES A CORROSION-PROTECTIVE COMPOSITION COMPRISING A RELATIVELY VOLATILE NON-POLAR LIQUID CARRIER AND AN EFFECTIVE CORROSION-INHIBITING AGENT, THE IMPROVEMENT WHICH COMPRISES UTILIZING AS THE CORROSION-PREVENTIVE COMPOSITION A COMPOSITION COMPRISING NORMALLY LIQUID POLAR AND NON-POLAR VEHICLE BOILING BELOW 600* F. AND FROM ABOUT 0.1% TO 2% BY WEIGHT OF A POLYVALENT METAL-HYDROXY AROMATIC MONOCARBOXYLIC ACID SALT. 